The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structures.
In the past, the semiconductor industry formed vertical MOS transistors with various device structures using various semiconductor processing methods. The prior vertical MOS transistors generally had a field oxide region that was positioned to overlie a portion of a field termination region of the vertical MOS transistor. These field oxide regions were formed by thermal oxidation. The field oxide regions were used to reduce electric fields in the termination region and to assist in providing a high breakdown voltage for the vertical MOS transistor. However, forming these thermally grown field oxide regions typically required at least one or more masks and related processing steps which increased the cost of the vertical MOS transistor.
Accordingly, it is desirable to have a vertical MOS transistor that has fewer processing steps and that has a lower cost.
For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action. For clarity of the drawings, doped regions of device structures are illustrated as having generally straight line edges and precise angular corners. However, those skilled in the art understand that due to the diffusion and activation of dopants the edges of doped regions generally may not be straight lines and the corners may not be precise angles.
In addition, the device of the present invention will be illustrated to show either a cellular design (where the body regions are a plurality of cellular regions) or a single body design (where the body region is comprised of a single region formed in an elongated pattern, typically in a serpentine or a stripe pattern). However, the device of the present invention will be described as a single base design throughout the description for ease of understanding. It should be understood that it is intended that the present invention encompass both a cellular design and a single base design.